Durable hearing response was achieved in more than one-third (36%) of patients with neurofibromatosis type 2 (NF2) and hearing loss who were treated with bevacizumab, according to results of a study involving 14 patients. Bevacizumab is an anticancer drug that halts blood vessel growth.1
An estimated 1 in 25,000 people will develop NF2. This hereditary tumor syndrome progresses to deafness in virtually every patient because of vestibular schwannomas, tumors that grow on the nerves responsible for hearing. These tumors arise from Schwann cells, which support and insulate the nerves. In addition to deafness, the tumors also disrupt balance and compress the brain stem.
“Our study shows that the hearing loss suffered by at least a subset of these patients isn’t permanent and that there is hope of reversing it,” says Jaishri Blakeley, MD, director of the Johns Hopkins Comprehensive Neurofibromatosis Center and associate professor of neurology, neurosurgery, and oncology at the Johns Hopkins University School of Medicine in Baltimore, Maryland. “We made life-changing hearing restoration our priority measure of success with this trial rather than relying on outcomes that may not affect a patient’s life, such as change in tumor size.”
The protein VEGF is produced at high levels by vestibular schwannomas. VEGF promotes blood vessel growth that feeds tumors, and bevacizumab reduces VEGF levels in certain tumors and in wet macular degeneration, a blinding eye condition.
For this study, 14 patients (4 males and 10 females) age 14 to 79 years with NF2 and progressive hearing loss were enrolled. The patients were treated with bevacizumab 7.5 mg/kg IV every 3 weeks for 48 weeks, then observation for 24 weeks. This dose is lower than what cancer patients receive.
Clinically important adverse events occurred in 3 patients and were most likely due to the treatment: high blood pressure in 2 patients, and excessive bruising and bleeding in 1 patient.
Hearing evaluations revealed an average score for word recognition of 60% at the start of the trial, with only 4 patients having serviceable hearing. Sustained hearing improvement occurred for 5 patients (36%) with the treatment, and 12 of the patients achieved serviceable hearing in the ear that was previously non serviceable.